Weight-Based Guide Overestimates Endotracheal Tube Tip Position in Extremely Preterm Infants

To evaluate the association between endotracheal tube (ETT) tip position and adverse pulmonary outcomes using chest X-ray (CXR) in extremely preterm infants in whom ETT insertion length was estimated using weight + 6 guide (adding 6 cms to the infant's weight in kg).

CXRs of 85 infants performed in the first week were reviewed for right-sided atelectasis, air leaks, and uneven lung inflation. The first CXR was later reviewed to document the ETT tip. Regression analysis was performed to find the association between ETT tip position and adverse outcome after adjusting for other confounders.

Forty (46%) infants had ETT tip placement between the first and second thoracic vertebrae (optimal position) compared with 45 (53%) who had the ETT tip placement outside this range (suboptimal position). Infants with suboptimal ETT were ventilated for a longer period (6.1 vs. 15.9 days; p = 0.004). The odds of adverse outcomes was 11.6 (95% confidence interval: 3.03, 44.1) times higher among infants who did not have ETT at the optimal position compared with infants who had ETT at the optimal position.

Weight + 6 guide is not recommended to estimate ETT insertion length in extremely preterm infants. Gestation-based guide may be more appropriate to estimate ETT insertion length in this group of infants.